Google added the OpenID option to Blogger comment. According to Wikipedia, OpenID is a "decentralized single sign-on system. Using OpenID-enabled sites, web users do not need to remember traditional authentication tokens such as username and password. Instead, they only need to be previously registered on a website with an OpenID "identity provider" (IdP). Since OpenID is decentralized, any website can employ OpenID software as a way for users to sign in; OpenID solves the problem without relying on any centralized website to confirm digital identity."
OpenID is great because it allows you to use a single account to sign in to multiple sites without worrying about passwords. The system has been developed by Brad Fitzpatrick for LiveJournal (Brad now works at Google).
To enable the OpenID integration in Blogger, you need to visit draft.blogger.com, edit the Settings for your blog, choose the Comments tab and select "Anyone" (allows anonymous comments) or "Registered users". I enabled OpenID for this blog, as you can notice if you try to post a comment.
Hopefully, this is a small step for a full integration with Google's authentication system.